Southwestern Ontario?s worst flooding in decades triggers an emergency, an evacuation and aggravation

The London Free Press

Updated: February 22, 2018

Two mallard ducks cross Wonderland Road just north of the Guy Lombardo Bridge after Thames River floodwaters closed the north-south artery in both directions Wednesday. (MIKE HENSEN, The London Free Press)

Flood-battered Southwestern Ontario might as well be the sixth Great Lake.

Thousands forced out in Brantford, the worst flooding in London in 40 years and potential trouble yet to come in low-lying Chatham-Kent lies downriver of all that water — the fallout of torrential rain and a massive snow melt across the region.

Wednesday, the worst was over in London, hit by its heaviest flooding since 1977.

It was the same in the tiny Lake Erie community of Port Bruce, southeast of St. Thomas, which dodged an evacuation order from high water triggered by ice jams.

But while drivers faced flooded-out roads and parking lots in London, that aggravation was nothing like the fallout in Brantford, another city flooded by ice jams in a river, where three neighbourhoods with nearly 5,000 residents were evacuated Wednesday in an emergency that left Ontario Premier Kathleen Wynne headed their way to visit flood-hit areas.

In Orangeville, northwest of Toronto, officials were bracing for tragedy as they scoured a swollen river for a three-year-old boy who went missing after a car he was riding in was swept off a road.

The heavy rains and mild weather that triggered the flooding caused headaches for officials at water treatment plants, which are sometimes overwhelmed by summer storms that send run-off and sewage into the system too fast to keep up, meaning it goes untreated or only partly treated into the Thames River.

In 30 years working at the city’s main Greenway plant, division manager Geordie Gauld said he’s never seen anything like it.

“This is the worst I’ve seen it,” he said. “The plants are backing up, so to speak, so the water level in the plants in some spots is probably 12 inches higher than it would be normally just because we can’t get it out of the plant.”

If the river water levels rise higher, they’ll look at ways to bypass sections of the plant to get the water out faster, Gauld said.

The treated wastewater they’re releasing into the river isn’t as treated as they’d typically aim for, Gauld said, but desperate times call for desperate measures.

“We are bypassing some of the processes in the plant just because of the volume,” he said.

Low-lying areas of London near the Thames River and its tributaries were inundated by water on Wednesday, with stretches of at least eight roads still closed, and the high water encroaching on areas such as the Western University campus.

Just west of Greenway, Wonderland Road was closed in both directions as river water swept over parts of the major artery. The city is warning road closings could last for days as the water recedes.

Bad as things appeared, however, they might have been worse if not for flood-control measures including holding water back at the Fanshawe Dam, which reduced the flow into the swollen Thames by one-third — volume that might otherwise have spilled over a long retaining wall along the north bank of the river near Harris Park.

“If we didn’t have Fanshawe Dam, if we weren’t able to keep back water in the reservoir, we would have overtopped the dikes,” said Upper Thames River Conservation Authority spokesperson Eleanor Heagy.

A month’s worth of rain fell on much of the region in mere days, combined with mild weather that soared above 10 C at its height and melted huge snowbanks accumulated during a brutal stretch of winter. Ice jams in fast-moving waterways cause the water to spill over banks and cause flooding.

The defences

Area conservation authorities equipped with flood-control measures, such as reservoir dams, have held back water to reduce its flow into major river systems such as the Thames, which runs down Southwestern Ontario’s spine to Lake St. Clair. The most flood-prone area, Chatham-Kent, also relies on defences that include a major floodwater diversion channel.

The outlook

The rain was expected to end Wednesday, with overnight snow in the region’s forecast — but don’t count on that sticking around. Temperatures are expected to rise to an above-seasonal 7 C by Friday and stay warm through the weekend, said Environment Canada meteorologist Geoff Coulson.

— — —

ELSEWHERE IN THE REGION

Port Bruce: The flooded Lake Erie community avoided an evacuation by clearing the ice and sediment from an ice jam. “I think we mitigated the damages quite nicely. The river is flowing good,” said Rick Cerna, local councillor and chairperson of the Catfish Creek Conservation Authority.

Chatham: Peak Thames River water levels are expected there and in Thamesville Friday, and in Dutton and Southwest Middlesex Thursday. Basement flooding is expected in Chatham for structures backing onto the Thames along King Street and lower roads near the river. The Lower Thames Valley Conservation Authority is operating a diversion channel to protect south-end Chatham, and a backwater dam and pumping station in the downtown protect Chatham’s south end. “We’re continuing to run the dams above and below Chatham to help . . . keep the levels down,” said spokesperson Bonnie Carey. “However, we’re still expecting some rainfall.”

With files by Trevor Terfloth, Chatham Daily News, and The Canadian Press

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